Fix up the merge conflict resolution
Merge pull request #2366 from systay/merge-fixup

Merge 2.0-maint into 2.1-master
Remove the QueryPlan factories from projection plans
Add availableSymbols back to logical plans
Removed uses of coveredIds
Merge pull request #2372 from jakub-/queryplan

QueryPlan refactorings
Remove subqueries from QueryGraph by introducing a lookup table for subqueries and an optional field for optional match
Fix: ronja should fail if there are more than a single predicate expression in or in a where clause